#include <stdio.h>

int main()
{
    int a = 21,i;
    printf("Game begin:\n");
    while(a>0)
    {
        do
        {
            printf("How many sticks do you wish wo take (1_%d)?",a>4?4:a);
            scanf("%d",&i);        
        }while(i>4||i<1||i>a);
        if(a-i>0)
        printf(" %d sticks left in the pile.\n",a-i);
        if((a-i)<=0)
        {
            printf("You have taken the last sticks.\n");
            printf("***You lose!\nGame Over.\n");
            break;
        }
        else
        printf("Computer take %d sticks.\n",5-i);
        a-=5;
        printf(" %d sticks left in the pile.\n",a);
    }
    
}